Respiratory System Anatomy and Physiology PDF

Anatomy and Physiology MODULE XII Respiratory System Overview Our body uses energy from the food we eat, but cells can obtain the energy from foodstuffs only with the help of the vital gas oxygen which allows for cellular respiration....

Anatomy and Physiology MODULE XII Respiratory System Overview Our body uses energy from the food we eat, but cells can obtain the energy from foodstuffs only with the help of the vital gas oxygen which allows for cellular respiration. Luckily, oxygen is found in relative abundance in the atmosphere and therefore in the air we breathe. However, when the cells use oxygen, they produce the gaseous waste carbon dioxide. If allowed to build up in the body, carbon dioxide would become toxic, so the bloodstream carries the carbon dioxide to the lungs to be exhaled and eliminated from the body. The respiratory system’s primary role, therefore, is to bring oxygen from the atmosphere into the bloodstream and to remove the gaseous waste by-product carbon dioxide. The respiratory system is closely interrelated with the heart and circulatory system. General Objectives At the end of the course, you should have:  described the anatomic structures and physiologic processes involved in physiologic concepts;  utilized basic anatomical facts and physiologic concepts and principles in the nursing care of individuals;  used an understanding of how human organ systems are interrelated to apply a holistic approach to human health; and synthesized ideas to make connection between knowledge of anatomy and physiology and real-world situations, including healthy lifestyle decisions and homeostatic balance. Learning Objectives After studying this lesson, you should have:  stated the basic functions of the components of the respiratory system,  differentiated between respiration and ventilation,  discussed the process of gas exchange in the alveolar level, and  explained the actual process of breathing. Discussion The respiratory system can be divided structurally into upper and lower division, and functionally into conducting division and a respiratory division. General Function To supply body cells with oxygen for their metabolic needs and to remove waste materials of cellular metabolism as well as carbon dioxide. Respiration – it is the overall exchange of gases between the atmosphere, the blood and the cells. The two Systems that share the responsibility of supplying oxygen and eliminating carbon dioxide are the respiratory and cardiovascular system. Page 128  Anatomy and Physiology MODULE XII Three Basic Processes of Respiration: 1. Ventilation/breathing – movement of air between the atmosphere and the lungs. Phases: a. Inhalation/inspiration – to move air into the lungs b. Exhalation/expiration – to move air out of the lungs 2. External respiration – the exchange of gases between the lungs and the blood. 3. Internal respiration – the exchange of gases between the blood and the body cells. Organs Concerned with External Respiration: 1. Conducting portion a. Nose d. trachea b. Pharynx e. bronchi c. Larynx 2. Respiratory portion – the lungs a. Alveolar ducts c. alveolar sacs b. Alveoli Nose Parts: 1. External nose – it has two openings called the nostrils or external nares. 2. Internal nares – it connects with the pharynx or throat posteriorly. Nasal septum – divides the external and internal nares into right and left nasal cavities. Vestibules – the anterior portions of the nasal cavities just inside the nostrils. Functions of the Vestibule: 1. It warms, moistens and filters air as it enters the nose. 2. It detects olfactory stimuli for the sense of smell. 3. Large hollow resonating chambers are present for creating speech sound. Vibrissae – nose hair that filters out coarse bodies like insects and dust particles as it enters the nose. Three Shelves inside the Nose: 1. Superior meatus – it is considered the olfactory region because its membrane is lined with olfactory receptors. 2. Middle meatus 3. Inferior meatus Goblet cells – cell present in the middle and inferior meatus secreting mucus that serve to trap particles and moistens the air. The nasolacrimal ducts and 4 paranasal sinuses empty into the nose. Paranasal Sinuses – air-filled spaces inside bones communicating with the nasal cavity. 1. Maxillary paranasal sinus – it is the largest located in the maxilla and opens into the middle meatus. 2. Frontal paranasal sinuses – it is located in the frontal bone 3. Ethmoid paranasal sinus – it is located in the ethmoid bone 4. Sphenoid – it is located in the sphenoid bone Page 129  Anatomy and Physiology MODULE XII Pharynx (throat) It is a tube approximately 5 inches long that begins at the internal nares and extends part way down the neck. Its walls are made of skeletal muscle lined with mucous membrane. It is a passageway for both air and food and forms a resonating chamber for speech sounds. Parts: 1. Nasopharynx – the uppermost portion which has four openings: 2 internal nares and 2 auditory or eustachian tubes. The pharyngeal or adenoid tonsils are located in its posterior wall. 2. Oropharynx – it lies behind the mouth with only one opening, the fauces, which connects with the mouth. It is a common passageway for food and air. It is where the palatine and lingual tonsils are found. 3. Laryngopharynx – it is the lowermost portion that connects with the larynx anteriorly and with the esophagus posteriorly. It serves as a connection between the mouth and the digestive tract and as a connection between the nose and respiratory system. Larynx (Voice Box) It is a triangular box connecting the pharynx with the trachea. Its walls are supported by nine pieces of cartilages; three pieces are single and three are paired. Three Single Cartilages: 1. Thyroid cartilage – it is the largest and is also known as the Adam’s apple. 2. Epiglottis – a large, leaf-shaped cartilage that lies on the tip of the larynx. The stem part is attached to the thyroid cartilage, but the leaf part is unattached and is free to move up and down like a trap door that forms a lid over the glottis – space between the vocal cords in the larynx and the opening over the true vocal cords. 3. Cricoid cartilage- a ring of cartilage that forms the lowermost walls of the larynx. It attaches to the first ring of cartilage of the trachea. Six Paired Cartilages: 1. Arytenoid cartilages – they are ladle- shaped and attach to the vocal cords and laryngeal muscles and by their action they move the vocal cords. 2. Corniculate cartilages – cone-shaped cartilages 3. Cuneiform cartilages – rod-shaped cartilages located in the mucous membrane fold that connects the epiglottis to the arytenoid cartilages. Page 130  Anatomy and Physiology MODULE XII The mucous membrane of the larynx is arranged in two pairs of folds. 1. Vestibular folds – false vocal cords (upper pair) 2. True vocal cords – lower pair where sound originates through its vibration. The pharynx, mouth, nasal cavities and the paranasal sinuses all function as resonating chambers. The movement of the tongue and cheeks also contribute to creating the individual quality of human speech. Air coming from the lungs causes the vocal cords to vibrate and produce sound. The greater the volume of air, the louder the sound. Pitch is controlled by tension on the true vocal cords. The stronger the tension, the higher the pitch. True vocal cords are thicker in men; they vibrate more slowly and produce a lower pitch than that in women. Trachea (Windpipe) It is a tubular passageway for air approximately 4.5 inches in length and about 1 inch in diameter. It is located anterior to the esophagus and extends from the cricoid cartilage of the larynx to the 5th thoracic vertebra, where it divides into right and left primary bronchi. Its smooth muscle and elastic connective tissue are encircled by a series of 16-20 horizontal incomplete rings of hyaline cartilage that resemble a stack of C’. The open part of the C’s face the esophagus and allow it to expand into the trachea during swallowing. Tracheostomy – an incision into the trachea creating a new opening for air to enter when a foreign object becomes caught in the trachea and cannot be expelled by the cough reflex. The Bronchi and the Bronchial Tree Two primary bronchi split from the trachea at the level of the superior border of the 5th thoracic vertebra, these are: 1. Right primary bronchus – more vertical, shorter and wider than the left. 2. Left primary bronchus – longer than the right On entering the lungs, the primary bronchi divide to form smaller bronchi called the secondary bronchi/lobar bronchi, one for each lobe of the lung tertiary/segmental bronchi bronchioles terminal bronchioles respiratory bronchioles 2-11 ducts or atria where numerous alveoli and alveolar sacs are found at its circumference. Alveolar sacs – it consists of 2 or more alveoli that share a common opening where gas exchange occurs. The alveoli are considered the functional units of the respiratory system. Page 131  Anatomy and Physiology MODULE XII The Lungs They are paired, spongy, cone-shaped, blue gray organ which completely fill the pleural spaces extending from the diaphragm to about 1 ½ inches above the clavicle. The right lung has 3 lobes and the left lung has 2 lobes. Right lung – thicker and broader than the left and a bit shorter because the diaphragm is higher on the right side. Left lung – thinner, longer and narrower than the right lung. Two pleural membranes enclosing and protecting the lungs: 1. Parietal pleura – outer layer attaching the lungs to the wall of the thoracic cavity. 2. Visceral pleura – it covers the lungs Pleural cavity – the space between the parietal and visceral pleura which contains a lubricating fluid called the pleural fluid. Bronchopulmonary segment – segment of lung tissue that each tertiary bronchi supplies. Lobules – small compartments of the bronchopulmonary segment which contains lymphatic vessels, arterioles, venules and bronchioles from a terminal bronchiole. Alveolar-capillary membrane/respiratory membrane – a membrane inside each alveolus that is coated with a fluid consisting of a mixture of lipoproteins called surfactant that prevents the alveoli from collapsing or sticking shut as air moves in and out during breathing. It is through this membrane in which respiratory gases move through the process of diffusion. Pleurisy/pleuritis – inflammation of the pleural cavity Disorders of the Respiratory System 1. Bronchitis – an inflammation of the bronchi. 2. Emphysema – destruction of the walls of the alveoli. 3. Cystic fibrosis – an inherited disease affecting the secretory cells of the lungs. Due to abnormal chloride ion secretions, the mucus becomes very thick or viscous. 4. Pulmonary fibrosis – replacement of lung tissue with fibrous connective tissue due to excessive exposure to asbestos, silica or coal dust (black lung disease). 5. Respiratory distress syndrome/hyaline membrane disease – common in premature infants caused by too little surfactant produced by the lungs and the lungs tend to collapse. 6. Pneumonia – refers to any infection of the lungs mostly caused by bacteria. 7. Whooping cough/pertussis – a lung infection caused by Bordetella pertussis. 8. Chronic obstructive pulmonary disease – a progressive disorder characterized by long-term obstruction of airflow, which results in diminished inspiration and expiration. It includes emphysema, asthma and chronic bronchitis. The most common causes are smoking and breathing in second hand smoke. Other causes include Page 132  Anatomy and Physiology MODULE XII exposure to dust and gases at the workplace, chronic air pollution and pulmonary infections. 9. Asthma- it is characterized by recurring spasms of difficulty of breathing with symptoms such as wheezing while inhaling and exhaling, shortness of breath and coughing. HYALINE MEMBRANE DISEASE PNEUMONIA Page 133  Anatomy and Physiology MODULE XII Self-Check Test I. Answer the following. (5 Points each) 1. Differentiate between respiration and ventilation. _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ____________________________________________________________________. 2. Discuss the process of gas exchange in the alveolar level. _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ____________________________________________________________________. Page 134  Anatomy and Physiology MODULE XII 3. Explain the actual process of breathing. _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ____________________________________________________________________. References Books 1. Ankney,J., Colbert, B., and Lee, K. (2007). Principles of anatomy and physiology, an interactive journey: New Jersey: Pearson Education Inc. 2. Rizzo, D. C. (2006). Fundamentals of anatomy and physiology: Michigan: Thomson Delmar Learning 3. Van De Graaf, K., Fox, S. I., and LaFleur, K. (1997). Synopsis of human anatomy and physiology: Chicago: Wm. C. Brown Publishers. Page 135